Articulated arm structure

ABSTRACT

925,740. Load handling machines. J. W. KAPPEN. Sept. 14, 1959 [Sept. 30, 1958], No. 31289/59. Class 78 (3). Each arm of a load lifting or supporting fork comprises sections 4, 6 hinged about pins 5, 7 and provided with releasable catches for retaining the sections in coaxial alignment with the arm at right angles to the plate 1. A plate 41 pivoted on the section 6, is provided with a lip 43 which engages a pin 12 on section 4, and a hook 42 which, when sections 4, 6 are aligned, surrounds pin 7, the plate being pivotable to the released position shown in Fig. 3, against the action of spring 44, by a manually operable lever 23, a rod 26 and a bell-crank 31. With the parts in the position shown in Fig. 6, this movement of the plate 41 is prevented by a wedge plate 14 located between the hook 42 and pin 7, and carried by a vertically slidable block 13, but when the aligned sections 4, 6 are swung out to a position perpendicular to plate 1, a pin 16 on block 13 is aligned with a hole (not shown) in bracket 2 allowing the block to be moved downward by a knob 48 (Fig. 3) to free the plate 14 from the hook, whereby subsequent actuation of lever 23 unlocks sections 4 and 6. The upper surface of the arm is provided with rollers 47 (Fig. 4). The Specification states that the arms can either form the fork of a fork lift truck, or be mounted for vertical movement along a mast.

June 26, 1962 J. w. KAPPEN ARTICULATED ARM STRUCTURE 2 Sheets-Sheet 1 Filed Sept. 30, 1958 INVENTOR. [lo/m w Kifff/ June 26, 1962 J. w. KAPPEN ARTICULATED ARM STRUCTURE 2 Sheets-Sheet 2 Filed Sept. 30, 1958 INVENTOR.

(lo/Ml n4 [Hf/27V BY 19 3,040,922 ARTHCULATED ARM STRUCTURE John Wiiiiam Kappen, 243 Kenwood Ave, Dayton 5, Ohio Filed Sept. 30, 1958, Ser. No. 764,453 18 Claims. (Cl. 214-731) This invention relates to an articulated arm structure incorporating improved detent mechanism rendering it particularly adaptable to effect improvements in lift arms or the like. While the invention will be illustratively described herein with reference to lift arms it is to be understood that the scope and application of the invention is not so limited nor is such intended.

Prior art devices in the nature of lift or support arms have evidenced certain problems in application to material handling due to their limited flexibility. For example, much material is transferred on pallets. -To move a pallet to lift arms by fork truck, the truck must be maneuvered close to the lift arm support structure and the pallet must be moved over and onto the lift arms. This is a relatively slow procedure. Also, the operation has its blind spots and there is a consequent danger of damage to either the lift arms or the support structure in the process. Further, if the arms are hinged, there is danger that they may be bumped and induced to fold or buckle, with possible resulting damage to the arms and to the material which they are intended to support.

The present invention provides an improved arm incorporating articulated linkage featuring highly advantageous detent mechanism. The invention imparts a substantial flexibility to lift arms and affords a high safety factor in the use thereof. The lift arm illustrated is double hinged and capable of being positively and fully locked at right angles to its support structure. Moreover, it is jointed so its outer portion may be disposed at right angles to its inner portion to facilitate material handling in conjunction therewith. It is noted that the invention, in one instance, enables pallets to be safely and swiftly moved by fork truck directly into the apparatus mounting the lift arms, which have had their extremities outwardly jointed topermit this. The arm extremities may then be quickly moved to engage under the pallet extremities in a position where they are locked at right angles to the support structure for safe swift lifting of the pallet as required. The detent mechanism employed enables positive positioning of the portions of the articulated arm, insuring complete safety in its operation. The invention structure produced is economical and efficient both in fabrication and operation.

A primary object of the invention is to provide improvements in articulated arm structures to render such structures simple and economical to fabricate, more efficientand satisfactory in use, adaptable to a Wide variety of applications and simple to operate and maintain.

A further object of the invention is to provide a control linkage incorporating improved detent mechanism.

Another object of the invention is to provide increased flexibility in use of lift or support arm structure.

An additional object of the invention is to provide a jointed arm having improved detent means for establishing the sections of the arm at required angles to each other as the occasion demands.

A further object of the invention is to provide improvements in detent mechanism.

A further object of the invention is to provide an articulated arm structure possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fully appear in the specification, the invenice tion intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein is shown one but obviously not necessarily the only form of embodiment of the invention;

FIG. 1 is a top perspective view of a lift arm in accordance with the invention;

FIG. 2 is a view similar to FIG, 1 with portions of the arm housing structure broken away to show the articulated linkage of the arm in a full locking position;

FIG. 3 is a view similar to FIG. 2 showing the articulated linkage in an unlocking condition;

FIG. 4 shows the arm of FIG. 1 in a right angle configuration;

FIG. 5 is a fragmentary view of the inner extremity of the arm showing the disposition of the hinge and detent mechanism of the invention as the arm is locked at right angles to its support;

FIG. 6 is a fragmentary view similar to FIG. 5 with the arm folded to its support;

FIG. 7 is a fragmentary schematic showing of the support bracket for the arm;

FIG. 8 is a plan detail view of a latch employed in the arm illustrated; and

FIG. 9 is a detail view of the latch operator.

Like parts are indicated by similar characters of reference throughout .the several views.

Referring to the drawings, a lift arm of an articulated nature is shown, pivotally connected to one end of a mast plate 1 merely for purposes of illustration. it will be obvious that the lift arm ordinarily will be used in pairs but only one arm assembly need be described to effect a complete disclosure of the invention.

Connected to each end of mast plate 1 are vertically spaced horizontally disposed plates 2. The plates 2 are parallel and project perpendicularly to the outer face of the plate 1 forming an inner support for an arm assembly 3 embodying the invention.

The arm assembly 3 includes an inner hinge section 4 pivotally connected to plates 2 by a pivot pin 5 and to an outer arm section 6 by a pivot pin 7.

The inner hinge section 4 includes v-erticaly spaced upper and lower plates 8 having identical axially extending projections 9 to one side of their ends outermost from plate 1. The arm assembly is shown as a left hand unit and the projection 9 is disposed to the inner side of the arm as illustrated. The plates 8 are vertically spaced by plate 10 connected adjacent their sides including projections 9.

The plate 10 has an outer extension 11 offset inwardly of plates 8. A cylindrical pin 12 is fixed to lie vertically of the outer end of the extension.

The inner pivot 5 is spaced outwardly of the inner end of plates 8, projecting vertically therethrough and through plates 2 which immediately abut and contain plates 8 at their outermost surfaces. The pivot pin 7 is parallel to pin 5 and in longitudinally aligned relation therewith, extending through plates 8 spaced slightly beyond the extremity of plate extension 11 and inwardly of projections 9.

A stepped block 13 slidably mounts on pin 5 intermediate plates 8 to have a latch plate 14 of an elongated rectangular nature extend forwardly therefrom parallel to the outermost sides of plates 8. The inner surface of the outer extremity of plate 14 abuts the surface of pin 7 most remote from plate 11. Block 13 has a downwardly stepped rear projection 15 with a pin 16 fixed thereto depending through an aperture 17 to the inner extremity of lower plate 8 in longitudinal alignment with pins 5 and E 7. Lower bracket plate 2 has an aperture 18 for receiving pin 16 when hinge section 4 of the arm is projecting perpendicularly relative plate 1 to lock the position of the hinge section 4 in a manner to be described. In the instance of the pin 16 depending in aperture 1% block 13 seats to lower plate 8.

The outer arm section 6 includes an elongated housing 19 of generally rectangular cross section tapering to its outermost end. A channel member 26 is to the surface of the extremity of housing 19 to have its parallel flanges 21 form a projecting extension forwardly and vertically therefrom.

A pivot pin 22 transversely connecting the flanges 21 adjacent their lower extremities extends through a sleeve 22' integrally connected to the rear upper surface of an outwardly angled plate operator 23. Below sleeve 22, plate 23 has a plate bracket 24 fixed to project perpendicularly from its rear surface. The uppermost edge of plate 24 has a notch 24- nesting a laterally projecting pin 25 on the projecting extremity of link 26 disposed longitudinally within housing 19 and extending towards its inner end. A guide plate 27 fixed to the inner wall of housing 19 provides a support and bearing for link 26 spaced inwardly from its projecting extremity.

The innermost end of link 26 extending rearwardly from plate 27 is offset to one side of housing 19 and has a pin 28 projecting vertically from its upper surface at its extrernity. The pin 28 nests in the notch 29 in the extremity of one arm 30 of a bell crank lever 31 pivotally mounted on a pin 32 fixed vertically in housing 19 adjacent its side remote from the extremity of link 26 and rearwardly thereof. The other arm 33 of bell crank lever 31 has a notch 34 in its rearwardly projecting extremity nesting pin 35 projecting vertically from the upper surface of arm 36 of latch 37. Arm 36 connects integrally with a central block section 38 of latch 37 pivotally mounted to pin 39 to one side of housing 19 through the medium of an cecentric sleeve 40. A plate 41 fixed to the rear outer edge of block section 38 forms a section of the outer housing 19 to its inner side in the arm illustrated. The inner surface of plate 41 has a plate type hook 42 projecting inwardly of housing 19. A spring 44- engages to guide plate 27 and connects to link 26 inwardly thereof to normally bias link 26 outwardly of housing 19.

The pivot pin 7 projects in vertically connecting relation to rear extensions of the upper and lower sections of housing 19 at their inner extremities which abut and contain the outermost extremities of plates 8 of hinge section 4.

When the complete arm assembly projects perpendicular to plate 1, hook 42 is disposed about and in spaced relation to pivot pin 7 while an inwardly projecting lip 43 on the rear extremity of plate 41 engages about pin 12 on plate extension 11 of hinge section 4. Also, at this time, plate 14 is normally wedged between hook 42 and pin 7 to prevent movement of plate 41 outwardly of housing 19.

Projections 9 on plates 8 seat in notches in housing 19 at its inner end to prevent the arm section 6 folding inwardly on section 4 as illustrated. Thus, the section 6 can only hinge outwardly from a coaxial relation with section 4.

The housing 19 of the arm extension 6 is provided with spaced longitudinally aligned U-shaped channel members 45 fixed to the upper surface thereof. The legs of the U-shaped channel members project vertically from the housing 19 and are bridged by transverse pivot pins 46 spaced longitudinally thereof mounting rollers 47. A similar device in the form of a U-shaped channel member mounting rollers 47 is fixed to the upper plate 2 in longitudinal alignment with those on the housing 19. The rollers 47 mutually project to define a relatively friction free upper surface to the extension arm.

Referring to FIGS. 6 and 7 of the drawings, the assembly 3 can be folded into the mast plate 1 to lie parallel thereto. The detent elements are associated as shown in FIG. 6 wherein the latch plate 14 is wedged between the pin 7 and the hook 42 on latch plate 41 to lock the sections 4 and 6 of the arm together for conjoint movement. Noting FIG. 7, when the arm is disposed in this position the pin 17 extends through aperture 16 in lower plate 8 to seat on the upper surface of lower plate 2 out of alignment with the a erture 18 therein. The sections 4 and 6, locked together in coaxial relation, may be swung outwardly to project at right angles to the mast plate 1.

The plate 161 of the hinge section 4 has a slot 43 extending vertically therein between the plates 3. A pin 4-9 fixed to the latch block 13 projects through the slot 48. When the arm sections 4 and 6 are disposed at right angles to the plate 1 the pin 49 may be moved downward in slot 43 to move the block 13 and project connected pin 16 into the aperture 18 in lower bracket plate 2 which is in alignment therewith at this time. By depression of the operating plate 23, bracket plate 24 nesting pin 25 on the link 26 thrusts the link 26 inwardly of the housing 19 to pivot bell crank lever 31 in a counterclockwise direction, noting FIG. 3 of the drawings, to eccentrically pivot the latch plate 41 outwardly relative the housing 19 about the pin 39. This is enabled due to the fact that the block 13 seats to the lower plate 8 of the hinge section 4- upon projection of the pin 16 into the aperture 18 of bracket plate 2. This moves the latch 14- down out of its wedging relation between pin 7 and the hook 42 on the plate 41. The arm section 6 is thus disengaged from. the section 4 and may be pivoted outwardly to be disposed at right angles relative thereto.

As in the example previously referred to, a pallet may be moved directly into the supporting structure for lift arms and positioned to bridge the space Where the arm sections 6 are normally disposed. The pallet having been swiftly deposited, the sections 6 of the arms to either end of the plate 1 may be pivoted inwardly under the respective ends of the pallet to be locked at right angles to the plate 1 forming an axial extension of the hinge section 4. The locking action is facilitated due to the bias of the spring 44 and the link 26 to urge the plate 41 inwardly to housing 19 in conjunction with the fact that the hook 42 as the arm section 6 is swung outwardly merely moves around the pivot pin 7 and is guided thereby throughout the swing movements of the section 6.

The advantage of the invention in application to a lift arm structure should be readily obvious. Its versatility and flexibility in use is made readily apparent from the fact that the whole arm assembly may be hooked inwardly to the support structure from which it is intended to project when it is not desired to use it. Further the arm sections therein are normally locked together. When they are swung outwardly into a position at right angles to the support structure, the pin 16 serves to provide means for locking the complete assembly in this position. Also, the section 6 of the arm may be jointed outwardly subsequent to a simple release of the latch plate 41. When the lift arm is used in pairs and lowers a pallet to a wheeled structure at ground level, by merely swinging out sections 6 the pallet can be quickly and simply towed away. It is believed that the advantages are obvious in each instance. The articulated linkage which is embodied in the particular arm structure obviously may have other applications and operate in a similar manner in such other applications.

It is believed that the invention structure and the improvements provided by the detent mechanism therein has been illustratively disclosed in a manner to enable one versed in the art to readily conceive the basic concepts thereof.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. An arm assembly including a plurality of pivotally related sections, means on said sections for interengaging to effect a coaxial relation thereof, wedge means on at least one of said sections for locking said interengaging means in a position to prevent relative angular disposition of said sections, control means for withdrawing said Wedge means from said interengaging means to free them for relative movement and further control means for disengaging one of said interengaging means to provide for angular disposition of one section relative another.

2. An ar-m assembly including a plurality of pivotally related sections, means on said sections for interengaging to effect a coaxial relation thereof, wedge means on at least one of said sections for locking said interengaging means in a position to prevent relative angular disposition of said sections, control means for withdrawing said wedge means from said interengaging means to free them for relative movement, further control means for disengaging one of said interengaging means to provide for relative angular disposition of one section relative another, means on said sections preventing relative angular disposition thereof in one direction, said disengaged one of said interengaging means being normally biased to effect an interengaged condition on coaxial disposition of said sections.

3. An arm assembly including an inner arm section, an outer arm section, pivot means connecting said sections, means preventing relative pivoting of said sections in one direction to provide for coaxial disposition of said sections, means on said outer section for disposing in relatively surrounding relation to said pivot means and means on said inner section operative to maintain said pivot surrounding means in fixed relation to said pivot means to lock said sections in coaxial relation.

4. An arm assembly including an inner arm section, an outer arm section, pivot means connecting said sections, means preventing relative pivoting of said sections in one direction to provide for coaxial disposition of said sections, means on said outer section for disposing in relatively surrounding relation to said pivot means, means on said inner section operative to maintain said pivot surrounding means in fixed relation to said pivot means to lock said sections in coaxial relation, means mounted to said outer section normally biasing said pivot surrounding means to a predetermined position Within said inner arm section operable on removal of the means maintaining the fixed relation of the means surrounding the pivot means to the pivot means to unlock said arm sections.

5. An arm assembly including a pair of arm sections, a pivot means connecting said am sections, a biased plate on one of said arm sections having a hook normally urged in surrounding spaced relation to said pivot means, and means on the other of said arm sections adjustable to wedge between said hook and said pivot means to prevent relative movement thereof.

6. An arm assembly including sections in jointed relation, means for locking said sections in coaxial relation, roller means mounted to one surface of at least a portion of said sections to provide for relatively friction free movement of a body thereon and control means for said lockmeans operative to selectively maintain the coaxial relation of said sections or provide for relative angular disposition thereof.

7. Apparatus for locking relatively pivotable units in coaxial relation having a pivot pin connection therebetween including, hook means pivotally mounted on one of said units, link means connected to said hook means, means connected to said link means biasing said hook means to normally dispose about the pivot pin, means on the other of said units to engage said hook means and pivot pin to lock them against relative movement, and lever means for moving said link means against said bias means on disengagement of said lock means from said hook means and pivot pin to urge said hook means from its normally disposed condition to provide for relative pivoting of said units.

8. Apparatus for controlling relative disposition of arm segments having a pivot pin connection including a plate element pivoted to one of the segments. having a hook element connected to curve about the pivot pin, lever means connected to said plate element biased to induce a normal spacing between the pivot pin and said hook element and a plate element on the other of said segments adjustable to wedge between said hook element and the pivot pin to prevent relative movement thereof to thereby lock the segments in coaxial relation.

9. The structure as set forth in claim 8 and means for moving said plate element from its wedging relation between the pivot pin and said hook element and further means connected to said lever means to bias said hook element to said pivot pin on movement of said wedge plate element to provide for relative angular disposition of said arm segments.

10. An arm assembly including a support bracket, an

inner arm section pivoted to said bracket, means on said inner arm section engageable with said bracket to lock said arm section at right angles thereto, a. pivot pin vertically of said inner arm section to the outer end thereof, an outer arm section pivoted to said pivot pin, said arm sections having means interengaging to prevent relative pivoting thereof in one direction establishing a coaxial relation thereof and relatively adjustable means in said arm sections for interengaging to one side of said pivot pin to lock said arm sections in said coaxial relation.

11. An arm assembly including a support bracket, an inner arm section pivoted to said bracket, means on said inner arm section engageable with said bracket to lock said arm section at right angles thereto, a pivot pin vertically of said inner arm section to the outer end thereof, an outer arm section pivoted to said pivot pin, said arm sections having means interengaging to prevent relative pivoting thereof in one direction establishing a coaxial relation thereof, relatively adjustable means in said arm sections for interengaging to one side of said pivot pin to lock said arm sections in said coaxial relation, roller means fixed to the uppermost surface of at least one of said arm sections and containment means on the outer extremity of said outer arm section. 7

12. An arm assembly including, a hinge section, an outer arm section connected to said hinge section, said outer arm section having a housing, link means projecting relative said housing extending longitudinally thereof, a plate section in said housing to its inner end, a pivot pin vertically of said hinge section providing a pivot connection of said outer arm section thereto, a hook on said plate section to its inner side, a bell crank lever connecting said link and said plate section, means biasing said link, lever and plate section to cause said hook to encircle said pivot pin, a plate element vertically adjustable to one side of the pivot pin to wedge :between said hook and pivot pin when said hinge section and said arm section are coaxially disposed to lock them in such position.

13. An arm assembly including, a hinge section, an outer arm section connected to said hinge section, said outer arm section having a housing, a link projecting relative said housing extending longitudinally thereof, a plate section in said housing to its inner end, a pivot pin vertically of said hinge section providing a pivot connection of said outer arm sectionthereto, a hook on said plate section to its inner side, a bell crank lever connecting said link and said plate section, means biasing said link, lever and plate section to cause said hook to encircle said pivot pin, a plate element vertically adjustable to one side of the pivot pin to Wedge between said hook and pivot pin when said hinge section and said arm section are coaxially disposed to lock them in such position, means on said arm section and said hinge section preventing pivoting thereof in one direction, means connected to said wedge plate to move it from a Wedging position, said hook and pivot pin being adapted to provide for pivoting of said outer arm section relative said hinge section in an opposite direction on movement of said wedge plate therefrom.

14. The structure as set forth in claim 13 and roller means mounted to and spaced longitudinally of said outer arm section to provide a friction free upper surface thereon.

15. The structure as set forth in claim 13 and means providing an eccentric pivot for said plate section.

16. Apparatus for locking relatively pivotable units having a pivot connection in coaxial relation including a first latch means pivotally mounted on one unit, a second latch means fixed on the other unit, means biasing said first latch means fixed on the other unit, means biasing said first latch means to normally engage said second latch means to fix the units in coaxial alignment, said first latch means having a hook portion normally disposed about said pivot connection and means on one of said units for wedging between said hook portion and pivot connection to prevent disengagement of said latch means.

17. An arm assembly including arm elements having a pivot pin forming a connection therebetween, a first latch means on one of said elements, a second latch means on the other of said elements, means biasing one of said latch means to normally engage the other of said latch means to fix said elements in coaxial alignment, one of said latch means including a hook portion normally disposed about said pivot pin when said latch means are engaged to fix said elements in coaxial alignment and means on one of said elements for wedging between said hook portion and pivot pin to prevent disengagement of said latch means.

18. An arm assembly including a pair of relatively pivotable sections adapted for disposition in coaxial alignment having a pivot pin forming a connection therebetween, hook means pivotally mounted on one of said ann sections having link means connected thereto, means connecting to said link means biasing said hook means to a normal disposition about the pivot pin, means on the other of said artm sections to lock said hook means in its normal position about said pivot pin and means for moving said link means against said bias means, on disengagement of said lock means from said hook means, operative to displace said hook means from its normal disposition about the pivot pin to provide for relative pivoting of said arm sections.

References Cited in the file of this patent UNITED STATES PATENTS 207,390 Carlton et a1 Aug. 27, 1878 623,189 Smith Apr. 18, 1899 1,060,641 Sladden May 6, 1913 2,605,918 Roscoe Aug. 5, 1952 2,613,828 Elliott et a1. Oct. 14, 1952 2,772,767 Seifert Dec. 4, 1956 2,874,851 Scheurpflug Feb. 24, 1959 2,888,151 Morris May 26, 1959 FOREIGN PATENTS 324,368 Switzerland Oct. 31, 1957 

